Plane passengers were horrified when the flight crew on their plane waiting to take off in south-central Russia told them it was 'perfectly normal' that the aircraft was filling with smoke.

Some concerned passengers filmed the smoke making its way through the Angara Airlines cabin before taking off from Irkutsk, a city in Russia's Irkutsk Oblast region.

Flight - Attendants - Passengers - Nothing - Plane

Flight attendants initially told passengers there was nothing to worry about, but the plane was later replaced, resulting in a three-hour delay to the flight's destination of Ust-Kut, also in Irkutsk Oblast.

Some people reportedly started screaming, 'We are on fire! We are on fire!' at the sight of the smoke.

Smoke - Passengers - Rear - Aircraft - Antonov

The smoke was first noticed by passengers sitting at the rear of the aircraft - an Antonov An-24.